The overall objectives of this work are to explain the mechanism of action of the bacterial ribosome in terms of the chemical structures of its component macromolecular parts, and to understand the chemical basis of the mutual interaction of these components. The specific goals set for this year were the continuation of our efforts to identify ribosomal proteins involved in specific ribosomal functions, and to establish an approach to the identification of sites within the ribosomal RNA which are involved in specific functions.